The present invention relates to liquid handling members intended to be used in devices for handling urine. In particular, the present invention relates to those liquid handling members which are used for initial acquisition of the urine. The present invention further relates to devices for handling urine such as diapers, training pants, adult incontinence devices, bed mats, and the like which comprises the liquid handling members of the present invention.
Devices for handling urine such as diapers, training pants, adult incontinence devices, bed mats, and the like are well known in the art and are frequently used for example for babies, toddlers, incontinent persons, and bed-ridden persons. Typically, these devices comprise liquid handling members which are specifically designed for the rapid initial acquisition of urine disposed onto the device.
It has been recognized in the prior art that it is beneficial for example for the wearing comfort of such a device for handling urine to transport the acquired urine away from the point of acquisition already in the liquid handling member. Providing sufficient void space in the liquid handling member below the point of acquisition requires the liquid acquisition member to have a high caliper and hence to be very bulky. This problem can only be avoided if the acquired urine is transported away from the point of acquisition in a direction parallel to the surface of the liquid handling member.
The most commonly used mechanism for liquid transportation is capillary pressure. It is to be noted in this context that liquid transportation requires high capillary suction which in turn requires small capillaries to build up that suction. But in the case of liquid handling members which are intended for liquid acquisition large capillaries are needed to provide the void space for quickly acquiring the urine. Thus, in the case of the above described liquid handling members wicking liquid away from the point of liquid acquisition by means of capillary pressure is not very efficient.
As a result, it may be observed in prior art devices for handling urine that only a small fraction of the x, y-dimension of the liquid handling member is actually used when the first gush of urine is acquired. Hence, the void volume and liquid acquisition performance of the liquid handling member is not fully utilized.
It is therefore an object of the present invention to provide a liquid transport member which overcomes the problems posed by the prior art.
It is a further object of the present invention to provide a liquid handling member which distributes already the first gush of urine over a large fraction of its x, y-dimension.
It is a further object of the present invention to provide the liquid handling member which can acquire liquid while maintaining a relatively small wet caliper.
It is a further object of the present invention to provide a device for managing body liquids which comprises a liquid transport member of the present invention.
The present invention provides a liquid handling member for use and device for handling urine. The liquid handling member has an x, y-dimension of at least 60 square centimeters and the liquid handling member has a first gush distribution area of at least 80 percent of said x, y-dimension according to the member liquid distribution test defined herein.
The present invention provides a liquid handling member for use and device for handling urine. The liquid handling member has an x-dimension of at least 15 centimeters and the liquid handling member has a first gush distribution length of at least 80 percent of said x-dimension according to the member liquid distribution test defined herein.
The present invention further provides a device for handling urine comprising a first member for temporary storage of the acquired urine. The first member has an x, y-dimension of at least 60 square centimeters. The first member further has a first gush distribution area of at least 80 percent of said x, y-dimension of said acquisition member according to the member liquid distribution test defined herein.
The present invention further provides a device for handling urine comprising a first member for temporary storage of the acquired urine. The first member has an x-dimension of at least 15 centimeters. The first member further has a first gush distribution length of at least 80 percent of said x-dimension of said acquisition member according to the member liquid distribution test defined herein.
The present invention is described in the following by means of a variety of different embodiments and by means of a variety of different features. Further embodiments of the present invention may be obtained by combining features of one embodiment with features of another embodiment disclosed herein and/or with other features disclosed herein. These further embodiments are considered to be implicitly disclosed herein and hence form part of the present invention. It will be apparent to the skilled person that combinations of certain features may lead to non-functional articles not forming part of this present invention.
The following description is adopted for devices for handling body liquids of the baby diaper type, and in particular for devices intended for babies in the weight range of about 9-18 kg. Nonetheless, the skilled person will be able to readily adopt it for other purposes, such as for other sizes, or adult incontinence applications. The average gush size for the above babies is 75 ml, the 95 percentile of their gush size is 110 ml. The average urination rate for the above babies is 15 ml per second, the 95 percentile of their size is 22 milliliters per second. In adult incontinence context, the average gush size is 110 milliliters and average urination rate is at 22 ml per second. Nonetheless, gushes in the adult incontinence context may be up to 180 milliliters with peak rates up to 40 ml/s.
The present invention provides a liquid handling member which is intended to be used for the initial rapid acquisition of liquid gushes disposed onto a device for handling urine. The present invention further provides a device for handling urine comprising such a liquid handling member. The device of the present invention may be used for example as diapers, training pants, adult incontinence devices, or the like.
The term xe2x80x9cliquid handling devicexe2x80x9d as used herein refers to devices which are designed to handle body liquids such as urine, menses, feces, and the like. Handling body fluids includes but is not limited to acquiring, distributing, and storing the body liquids.
The device for handling urine according to the present invention further comprises a liquid acquisition region.
The term xe2x80x9cacquisition regionxe2x80x9d as used herein refers to that region of the device for handling urine according to the present invention which is intended to first come into contact with the exudated body liquids. In many cases, the acquisition region of the device is distinguished from other regions of the device by for example different materials. In this case, the acquisition region comprises the total surface area covered by the specific acquisition material. In cases where the acquisition region is not distinguished from other regions in their readily apparent way, the acquisition region is considered to be that region which is centered around the intended loading point of the device, which is about a third of the length of the device long, and which spans over the entire width of the device. In case, more than one loading point is foreseen in the intended use of the device, the geometric average of these loading points is to be used for the definition of the acquisition region.
For the purpose of the present invention, a Cartesian coordinate system is defined as follows. The. z-direction is defined to be perpendicular to the surface of the acquisition region at the intended loading point. The x-direction is defined to coincide with the longitudinal dimension of the device for handling urine. In the case of a diaper, the x-direction runs from the front region of the device (which comes into contact with the front waist region of the wearer during use) to the back region of the device (which comes into contact with a back waist region of the wearer during use). Accordingly, the y-direction coincides with a transverse dimension of the device for handling urine which runs from the left to the right of the wearer during use. It is to be understood in this context that this Cartesian coordinate system is only a truly Cartesian coordinate system when the device is in the flat out configuration. For typical in use conditions, the configuration of the device is such that x-, y-, and z-direction as defined above only form a locally perpendicular set of coordinates.
A liquid handling member of the present invention rapidly distributes acquired liquid over large fraction of its x, y-dimension. This rapid distribution of liquid is independent of gravitational forces acting on the liquid. This enables the liquid handling member of the present invention to achieve this rapid distribution also in those in use configurations in which the liquid has to be distributed against gravity. For the purposes of this invention, the ability of a liquid handling member to rapidly distribute liquid over its x, y-dimension or along its x-dimension is quantified by the member liquid distribution test defined hereinafter. A liquid handling member of the present invention has a liquid distribution ratio of at least 80 percent, preferably a liquid distribution ratio of at least 90 percent, more preferably liquid distribution ratio of at least 95 percent, is most preferably liquid distribution ratio of at least 100 percent.
The liquid handling member of the present invention has a x, y-dimension of at least 60 square centimeters, preferably of at least 90 square centimeters, more preferably of at least 130 square centimeters, most preferably of at least 180 square centimeters. The surface area dimensions are intended to be used for devices having a target user group of babies in the weight range between 9 and 18 kg. For other target user groups which may have different urination patterns as can be seen for example in different gush sizes, the aforementioned surface area dimensions have to be adopted accordingly. Alternatively, the liquid handling member of the present invention has a x-dimension of at least 15 centimeters, preferably of at least 18 centimeters, more preferably of at least 20 centimeters, most preferably of at least 25 centimeters. Again, this x-dimension is given for intended user group of babies in the weight range between 9 and 18 kilograms. For other intended user groups, this dimension also needs to be adopted accordingly.
It is further desirable for the liquid handling member of the present invention to exhibit a high absorbent capacity in order to be able to a readily acquire larger loads of liquid. For the purpose of this invention, the absorbent capacity of the liquid handling member is quantified by the demand absorbency test defined hereinafter, Preferably, the liquid handling member of the present invention has an absorbent capacity of at least 50 ml, more preferably of at least 75 ml, yet more preferably of at least 110 ml, most preferably of at least 180 ml.
It is further desirable for the liquid handling member of the present invention to exhibit a high trans-planar and in-plane permeability in order to be able to rapidly distribute acquired liquid over its x-and, y-directions. For the purposes of this invention, the permeability is measured via the permeability test defined in PCT patent application No. US98/13497 filed on Jun. 29, 1998 incorporated herein by reference. Preferably, the liquid handling member of the present invention has a permeability of at least 10 Darcy, more preferably a permeability of at least 50 Darcy, most preferably a permeability of at least 100 Darcy.
It is desirable for the liquid handling member of the present invention to only have a small caliper, i.e. a small z-direction dimension. A smaller caliper of the liquid handling member leads to less bulk between the legs of the wearer. Preferably, the liquid handling member according to the present invention has a z-direction dimension of less than 30 mm, more preferably of less than 20 mm, most preferably of less than 15 mm.
It is desirable for the liquid handling member according to the present invention to have a y-direction dimension in the vicinity of the intended loading point which is as small as possible in order to not exhibit high bulk between the legs of the wearer. Preferably, the liquid handling member according to the present invention has a y-direction dimension in the vicinity of the intended loading point of less than 100 milliliters, more preferably of less than 80 milliliters, most preferably of less than 60 mm.
The present invention further provides a device for handling urine comprising a first member for temporary storage of the acquired during and a second member for the ultimate storage of the acquired urine. In this context, the liquid handling member of the present invention may be used for example as the first member of the device for handling urine.
Liquid Transport Member
In the following, a suitable embodiment of the liquid handling member will be described. The liquid handling member is assembled from an open celled foam material which is completely enveloped by a membrane. A suitable membrane material is available from SEFAR of Rxc3xcschlikon, Switzerland, under the designation SEFAR 03-20/14. A suitable foam material is available from Recticel of Brussels, Belgium, under the designation Bulpren S10 black. A suitable technique to completely envelope the foam material with the membrane material is to wrap the membrane material around the foam material and to subsequently heat seal all open edges of the membrane material. It will be readily apparent to the skilled practitioner to choose other similarly suitable materials. Depending on the specific intended application of the liquid handling member, it may also be required to choose similar materials with slightly different properties. After assembly, the liquid handling member is activated by immersing the liquid handling member in water or in synthetic urine until the liquid handling member is completely filled with liquid and until the membranes are completely wetted with liquid. After activation, a part of the liquid inside the liquid handling member may be squeezed out by applying an external pressure to the liquid handling member. If the activation of the liquid handling member was successful, the liquid handling member should not suck air through the membranes.
Other liquid handling members suitable for the purposes of the present invention are described for example in the PCT patent application No. PCT/US98/13497 entitled xe2x80x9cLiquid transport member for high flux rates between two port regionsxe2x80x9d filed in the name of Ehrnsperger et al. filed on Jun. 29, 1998, and in the following PCT patent applications co-filed with the present application entitled xe2x80x9cHigh flux liquid transport members comprising two different permeability regionsxe2x80x9d (PandG case CM1840MQ Ser. No. 09/720,186, pending) filed in the name of Ehrnnsperger et al., xe2x80x9cLiquid transport member for high flux rates between two port regionsxe2x80x9d (PandG case CM1841MQ Ser. No. 09/720,187, pending) filed in the name of Ehrnspergeret al., xe2x80x9cLiquid transport member for high flux rates against gravityxe2x80x9d (PandG case CM1842MQ) Ser. No. 09/720,188, now abandoned filed in the name of Ehrnsperger et al., xe2x80x9cLiquid transport member having high permeability bulk regions and high bubble point pressure port regionsxe2x80x9d (PandG case CM1843MQ) Ser. No. 09/720,189, now abandoned filed in the name of Ehrnsperger et al. All of these documents are enclosed herein by reference.
The particular geometry of the liquid handling member of the present invention can be varied according to the specific requirements of the intended application. If, for example, the liquid handling member is intended to be used in an absorbent article the liquid handling member may be defined such that its zone of intended liquid acquisition fits between the legs of the wearer and further that its intended liquid discharge zone matches the form of the storage member associated to it. Accordingly, the outer dimensions of the liquid handling member such as length, width, or thickness may also be adapted to the specific needs of the intended application. In this context, it has to be understood, however, that the design of the outer form of the liquid handling member may have an impact on its performance. For example, the cross section of the liquid handling member directly impacts on its flow rate.
For application of the liquid handling member in a device for handling urine according to the present invention, the liquid handling member may be combined with a storage member. The term xe2x80x9cliquid storage memberxe2x80x9d refers to a device which is capable of acquiring and storing liquid. The volume of the liquid storage member may vary with the amount of stored liquid such as by swelling. Typically, the storage member will imbibe the liquid by means of capillary suction and/or osmotic pressure. Other storage members may also use vacuum as a means to store the liquid. The liquid storage member is further capable of holding at least a portion of the stored liquid under pressure. Suitable storage members are well known in the art and may comprise for example a super absorbent polymeric material such as polyacrylate. The storage member may further comprise a fibrous structure, such as a pad of cellulosic fibers, in which the particulate superabsorbent material is dispersed. A suitable superabsorbent material is ASAP400 available from Chemdal Ltd., United Kingdom. In order to pick up the liquid discharged from the liquid handling member, the storage member may be placed in direct liquid communication with the intended liquid discharge zone of the liquid handling member.
Further examples of suitable superabsorbent polymers, often also referred to as xe2x80x9chydrogel forming polymerxe2x80x9d or xe2x80x9cabsorbent gelling materialxe2x80x9d, are described in U.S. Pat. No. 5,562,646 (Goldman et al.), issued Oct. 8, 1996 and U.S. Pat. No. 5,599,335 (Goldman et al.), issued Feb. 4, 1997.
In one embodiment of the present invention, the liquid handling member of the present invention is geometrically saturated or substantially geometrically saturated with free liquid. The term xe2x80x9cfree liquidxe2x80x9d as used herein refers to liquid which is not bound to a specific surface or other entity. Free liquid can be distinguished from bound liquid by measuring the proton spin relaxation time T2 of the liquid molecules according to NMR (nuclear magnetic resonance) spectroscopy methods well known in the art.
The term xe2x80x9cgeometrically saturatedxe2x80x9d as used herein refers to a region of a porous material in which the liquid accessible void spaces have been filled with a liquid. The void spaces referred to in this definition are those which are present in the current geometric configuration of the porous material. In other words, a geometrically saturated device may still be able to accept additional liquid by and only by changing is geometric configuration for example by swelling, although all voids of the device are filled with liquid in the current geometric configuration. A device for handling liquids is called geometrically saturated, if all porous materials that are part of the device and intended for liquid handling are geometrically saturated.
The term xe2x80x9cporous materialxe2x80x9d as used herein refers to materials that comprise at least two phasesxe2x80x94a solid material and a gas or void phasexe2x80x94and optionally a third liquid phase that may be partially or completely filling said void spaces The porosity of a material is defined as the ratio between the void volume and the total volume of the material, measured when the material is not filled with liquid. Non-limiting examples for porous materials are foams such as polyurethane, HIPE (see for example PCT patent application WO94/13704), superabsorbent foams and the like, fiber assemblies such as meltblown, spunbond, carded, cellulose webs, fiber beds and the like, porous particles such as clay, zeolites, and the like, geometrically structured materials such as tubes, balloons, channel structures etc. Porous materials might absorb liquids even if they are not hydrophilic. The porosity of the materials is therefore not linked to their affinity for the liquid that might be absorbed.
The term xe2x80x9csubstantially geometrically saturatedxe2x80x9d as used herein refers to a member in which at least 90% of the macroscopic void volume of the member are geometrically saturated, preferably at least 95% of the macroscopic void volume of the device are geometrically saturated, more preferably 97% of the macroscopic void volume of the device are geometrically saturated, most preferably 99% of the macroscopic void volume of the device are geometrically saturated.
In one embodiment of the present invention, the device for handling urine is a disposable absorbent article such as a diaper, a training pant, an adult incontinence device, or the like. Such an absorbent article may further comprise a liquid pervious topsheet, a liquid impervious backsheet at least partially peripherally joined to the topsheet. The absorbent article may further comprise an absorbent core which may serve as a storage member for the body liquid. Topsheets, backsheet, and absorbent cores suitable for the present invention are well known in the art. In addition, there are numerous additional features known in the art which can be used in combination with the absorbent article of the present invention such as for example closure mechanisms to attach the absorbent article around the lower torso of the wearer.